We’ve seen prior references to some or all people bitten by WNV-positive mosquitoes acquiring immunity to WNV (see, e.g., WEbMD and a California State site). Most WNV cases have unnoticed symptoms but as in the case of other viruses, one can assume the affected individual acquires immunity. Below is the most positive statement we have seen so far, from “Mosquitoes with West Nile Virus popping up across PA” by Jack Eble, Fox43 News, 7/5/18:
…there are no confirmed cases of West Nile Virus in people, statewide.
Dr. John Goldman, infectious disease specialist with UPMC-Pinnacle, said finding a positive case in a person can be hard to find.
“Most people who’ve had [West Nile Virus] aren’t aware of it. Once you’ve had it, you’re immune. You can’t get it again,” said Dr. Goldman.
He believes most people have become immune to West Nile Virus, slowing the spread of the illness.
In 2003, Pennsylvania had 236 people test positive for West Nile Virus.
But since then, the most confirmed cases was 60 in 2012….